There are a few ways you can apply oil to your hair to help protect it from damage.

First, applying oil to your hair before it's washed can help reduce the amount of damage it sustains during washing and while it's wet.

Interestingly, hair is most vulnerable to damage when it's wet. This is because of subtle, structural changes that occur when it absorbs water.

When you wet your hair, the thick, central cortex soaks up the water and swells, causing a structural change in the cuticle.

The hair cuticle is actually made up of flat, overlapping scales that are attached towards the root end of your hair and point towards the tip.

When the cortex of your hair absorbs water and swells up, these scales are pushed outward so they stick up. This makes wet hair much easier to damage, especially when brushing or styling.

Applying oil to your hair before you wash it can reduce the amount of water absorbed by the hair shaft and the degree to which the cuticle scales "stick up." This makes it less prone to damage while it's wet.

Second, coating your hair in oil after you wash it helps make it softer and smoother. This reduces the amount of friction caused by styling, making your hair less likely to snag and break ().

Bottom Line: Your hair is most vulnerable to damage when it's wet. Applying oil to your hair both before and after you wash it helps protect it from damage.

Coconut oil may also have other benefits for your hair. However, many of them haven't been examined in properly controlled studies.

Possible benefits include:

Lice prevention: One small study found that when combined with anise in a spray, coconut oil was 40% more effective at treating head lice than the chemical permethrin ().

Sun protection: UV filters can help protect your hair from sun damage. Some studies have found coconut oil to have a sun protection factor of 8, so putting it on your hair could be useful (, , ).

Dandruff treatment: Dandruff can be caused by an overgrowth of fungus or yeast on the scalp. While no studies have examined coconut oil specifically, it has antimicrobial properties and could be useful for treating dandruff (, ).

Hair loss prevention: Excessive grooming can damage the hair shaft, which in extreme circumstances can cause hair loss. Coconut oil can help keep your hair in good condition and prevent this.

It's also claimed that consuming coconut oil can be beneficial for hair health due to the nutrients it provides. However, there is little evidence that this is the case ().

Bottom Line: Coconut oil could help get rid of lice, protect your hair from the sun and reduce dandruff, but more studies are needed.

Coconut oil is generally considered safe to apply to your skin and hair ().

However, using too much could cause a buildup of oil on your hair and scalp.

This could make your hair greasy and dull, especially if you have very fine hair.

To avoid this, make sure you start with only a small amount and begin by rubbing the coconut oil through your hair, from the midsection to the ends. People with very fine hair may want to avoid putting coconut oil on their scalp altogether.

Furthermore, while it's normal to lose about 50–100 hairs a day, many people also report losing lots of hair when they use coconut oil.

But coconut oil is not usually the culprit. Simply applying the oil allows hair that has already detached from your scalp to fall away.

Bottom Line: Using too much coconut oil can make your hair greasy. It usually doesn't cause hair loss, but it can cause previously detached hair to fall away from your scalp more easily.

Here are a few ways to use coconut oil to help improve the health of your hair.

As a conditioner: Shampoo your hair as normal and then comb coconut oil through your hair, from the midsection to the ends.

As a post-wash detangler: After shampooing and conditioning your hair, rub a little coconut oil through your hair to protect it while you brush it.

As a hair mask: Rub coconut oil through your hair and let it sit for a few hours (or even overnight) before washing it out.

As a pre-wash hair protector: Rub coconut oil through your hair before you wash it.

As a scalp treatment: Before bed, massage a small amount of coconut oil into your scalp. Leave it overnight and wash it off with shampoo in the morning.

These techniques can be used regularly or once in a while (depending on your hair type) to give you beautiful, healthy and shiny hair.

The amount of coconut oil you'll need will depend on your hair length and type. Most people use just enough to cover the midsection to the ends of their hair to avoid their hair getting greasy.

The best approach is to start with the smallest amount you think you will need and gradually increase from there.

If you have short or very fine hair, you may need as little as one teaspoon. However, people with long, thick hair may want to use as much as two tablespoons.

There are also many different types of coconut oil to choose from. Some people prefer to choose a virgin (unrefined) coconut oil, as they also use it in their diet.

However, there aren't any specific studies on whether one type of coconut oil is better for your hair than another. Additionally, both unrefined and refined coconut oil have the same moisturizing properties.

Bottom Line: Coconut oil can be used as a conditioner, hair mask or scalp treatment to give you shiny, healthy hair.